Method and apparatus for power cutback in a simultaneous dual frequency band call

ABSTRACT

A method and apparatus can cut back power in a simultaneous dual frequency band call. The method may operate a dual frequency band transmit device. The method may include determining if a transmit frequency in a first frequency band from the device combined with a transmit frequency in a second frequency band from the device causes receiver desensitization at the device. The method may include determining if the transmit power in the first frequency band is above a threshold power. The method may include reducing maximum transmit power in the second frequency band by an amount proportional to transmit power in the first frequency band and transmit signal bandwidth in the second frequency band in only the portion of the second frequency band where a resultant frequency component can cause desensitization.

CROSS REFERENCE TO RELATED APPLICATION

This patent application is a continuation of U.S. patent applicationSer. No. 13/221,430 filed Aug. 30, 2011 by Dean E. Thorson and entitled“Method and Apparatus for Power Cutback in a Simultaneous Dual FrequencyBand Call.” This related application is hereby incorporated by referenceherein in its entirety, and priority thereto for common subject matteris hereby claimed.

BACKGROUND

1. Field

The present disclosure is directed to a method and apparatus for powercutback in a simultaneous dual frequency band call. More particularly,the present disclosure is directed to power cutback for a cellular callin a first frequency band simultaneous with a second frequency band.

2. Introduction

Wireless communication devices used in today's society include mobilephones, personal digital assistants, portable computers, gaming devices,and various other electronic communication devices. Such devices employmultiple transceivers that allow a device to transmit and receivesignals on different wireless networks. For example, a device caninclude a Code Division Multiple Access (CDMA) transceiver, a Long TermEvolution (LTE) transceiver, a Universal Mobile TelecommunicationsSystem (UMTS) transceiver, a Global Positioning System (GPS) receiver,an 802.11-based transceiver, and/or other transceivers.

Unfortunately, nonlinearities in a device's radio frequency circuitrycan cause receiver desensitization on certain channel combinations. Forexample, desensitization can occur when both the LTE and CDMAtransmitters are on and are at or close to full power. This receiverdesensitization can be a reduction in receiver sensitivity due to thepresence of a high-level off-channel signal overloading the radiofrequency amplifier or mixer stages. As a further example, receiverdesensitization can occur when a strong off-channel signal overloads areceiver front end and thus reduces the sensitivity to weaker on-channelsignals. One other example is when non-linearity in the transmittercircuitry can cause the transmit signals to mix, creating strong signalsthat fall within the device's receive frequency bands.

Hardware design has been implemented to minimize desensitization in asimultaneous dual frequency band call. However, with present technology,desensitization cannot be completely eliminated without degradingperformance of the individual transceivers when they are operatingalone.

Thus, there is a need for a method and apparatus for power cutback in asimultaneous dual frequency band call.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of thedisclosure can be obtained, various embodiments will be illustrated inthe appended drawings. Understanding that these drawings depict onlytypical embodiments of the disclosure and do not limit its scope, thedisclosure will be described and explained with additional specificityand detail through the use of the drawings in which:

FIG. 1 illustrates an example diagram of a system in accordance with apossible embodiment;

FIG. 2 illustrates an example block diagram of an apparatus inaccordance with a possible embodiment;

FIG. 3 shows a sample flowchart illustrating the operation of theapparatus of FIG. 2 in accordance with a possible embodiment; and

FIG. 4 shows a sample flowchart illustrating the operation of theapparatus of FIG. 2 in accordance with a possible embodiment.

DETAILED DESCRIPTION

A method and apparatus for power cutback in a simultaneous dualfrequency band call is disclosed. The method can operate on a dualfrequency band transmit device. The method may include determining if atransmit frequency in a first frequency band from the device combinedwith a transmit frequency in a second frequency band from the devicecauses receiver desensitization at the device. The method may includedetermining if the transmit power in the first frequency band is above athreshold power. The method may include reducing maximum transmit powerin the second frequency band by an amount proportional to transmit powerin the first frequency band and transmit signal bandwidth in the secondfrequency band.

FIG. 1 is an example block diagram of a system 100 according to onepossible embodiment. The system 100 can include a terminal 110, anetwork 120, a first base station 130, a second base station 135, and anetwork controller 140.

The terminal 110 can be a wireless communication device includingcellular and/or other wireless communication circuitry, such as CodeDivision Multiple Access (CDMA) circuitry, Long Term Evolution (LTE)circuitry, Universal Mobile Telecommunications System (UMTS) circuitry,Time Division Multiple Access (TDMA) circuitry, Frequency DivisionMultiple Access (FDMA) circuitry, Bluetooth circuitry, Wi-Fi circuitry,Global Positioning System (GPS) circuitry, and/or other wirelesscommunication circuitry. For example, the terminal 110 can be a mobilephone, a personal digital assistant, a laptop computer, a tablet, or anyother communication device that allows a user to communicate or performapplications using the terminal 110. As a further example, the terminal110 can be a wireless communication device, such as navigation device,gaming device, entertainment device, a wireless telephone, a cellulartelephone, a personal digital assistant, a pager, a selective callreceiver, or any other device that is capable of sending and receivingcommunication signals on an electronic network

The base stations 130 and 135 may be cellular base stations, a wirelesslocal area network access points, or any other devices that providesaccess between a wireless device and a network. For example, the basestation 130 can be a CDMA base station and the base station 135 can be aLTE or UMTS base station.

In an exemplary embodiment, the network controller 140 is connected tothe network 120. The controller 140 may be located at a base station, ata radio network controller, or anywhere else on the network 120. Thenetwork 120 may include any type of network that is capable of sendingand receiving signals, such as wireless signals. For example, thenetwork 120 may include a wireless telecommunications network, acellular telephone network, a CDMA network, a LTE network, a UMTSnetwork, a TDMA network, an FDMA network, a satellite communicationsnetwork, and other like communications systems. Furthermore, the network110 may include more than one network and may include a plurality ofdifferent types of networks. Thus, the network 120 may include aplurality of data networks, a plurality of telecommunications networks,a combination of data and telecommunications networks and other likecommunication systems capable of sending and receiving communicationsignals.

In operation, the terminal 110 can determine if a transmit frequency ina first frequency band from the terminal 110 combined with a transmitfrequency in a second frequency band from the terminal 110 causesreceiver desensitization at the terminal 110. The terminal 110 candetermine if the transmit power in the first frequency band is above athreshold power. The terminal 110 can reduce maximum transmit power inthe second frequency band by an amount proportional to transmit power inthe first frequency band and transmit signal bandwidth in the secondfrequency band.

For example, the first frequency band can be a CDMA frequency band orother frequency band. The second frequency band can be a LTE frequencyband, a UMTS frequency band, or other frequency band. The maximum LTEoutput power can be cut back when certain channel combinations areencountered during a Simultaneous CDMA Voice/LTE Call (SVLTE). A methodfor cut back power can be performed using the following information: 1.The fact that the terminal 110 is in an SVLTE call; 2. The CDMA channelnumber; 3. LTE uplink Resource Block (RB) allocation, such as the numberof RBs and RB location; 5. The CDMA output power, which can becalculated from open loop and/or closed loop power control; 6.Non-volatile memory location elements dictating the minimum CDMA powerat which LTE cutback will start; and/or other useful information.

The calculation for LTE power cutback can be as fast as open loop powercontrol because de-sensitization can otherwise occur in the receiveruntil the LTE power is cutback if the phone goes into a deep fade whereCDMA power suddenly increases above the threshold.

LTE output power can be cut back starting at a given CDMA output powerwhich can be dependent upon the phone design, such as dependent on frontend losses, Surface Acoustic Wave (SAW) Duplex Filter Intercept Point3(IP3), attenuation of LTE/CDMA Diplexer, antenna isolation for dualantenna configuration, and other information. Three non-volatile memorylocation elements can be used. Two elements can be used for thethreshold CDMA output power at which LTE output power can be cut back toavoid either CDMA de-sensitization or LTE de-sensitization and oneelement can be used that gives the bandwidth, such as in tens of Khz,around the receive CDMA channel to be protected. Embodiments can scalethe cutback according to the number of assigned uplink RBs. As moreuplink RBs are assigned, the LTE output power can be spread, andconsequently, LTE power may not have to be cut back as much.

According to some embodiments, the algorithm can disable the maximumpower cutback for LTE de-sensitization and can ignore limitationscreated by Signal Absorption Radio (SAR) and antenna constraints, toallow for minimal implementation impact on the CDMA and LTE sub-systems.

The following terms can be used for the following example embodiment:

-   LTE_PWR_RED_SVLTE: The amount of power cutback that can be applied    to the uplink LTE output power from max LTE output power.-   P_MIN_CDMA_LTE: The threshold CDMA output power that can give the    desired LTE sensitivity at max LTE power during SVLTE. Any CDMA    power higher than this may degrade LTE sensitivity.-   P_MIN_CDMA_CDMA: The threshold CDMA output power that can give the    desired CDMA sensitivity at max LTE power during SVLTE. Any CDMA    power higher than this may degrade CDMA sensitivity.-   P_CDMA: CDMA uplink output power that is currently being transmitted    from the terminal.-   NUM_OF_RB: Number of uplink RBs to be transmitted.-   CHANNEL_NUMBER: CDMA Channel Number.-   INT_BW: Bandwidth of the interferer (in tens of KHz). Default can be    264, which is equivalent to 2,640,000 Hz.-   RB_NUM_LOW: The lowest RB number for a given CDMA channel,    CHANNEL_NUMBER, which might require LTE power cutback.-   RB_NUM_HIGH: The highest RB number for a given CDMA channel,    CHANNEL_NUMBER, which might require LTE power cutback.

According to some embodiments, the following procedure can beimplemented at a terminal MODEM:

-   -   1. Procedures for CDMA Side.        -   a. When any of the following messages are received, compare            the CHANNEL_NUMBER contained in the message to the current            operating channel. If different, then send a message from            the CDMA sub-system to the LTE sub-system containing the new            CHANNEL_NUMBER and the P_MIN_CDMA_CDMA information. The new            CHANNEL_NUMBER can be the CHANNEL_NUMBER contained in the            message. For example, the message can contain an updated            channel number, if it has changed. According to some            examples, the message may always contain the active CDMA            channel number, because it can be simpler to always include            that data.            -   i. Channel Assignment Message            -   ii. Extended Channel Assignment Message            -   iii. Handoff Direction Message            -   iv. Extended Handoff Direction Message            -   v. Global Handoff Direction Message        -   b. When transmitting above P_MIN_CDMA_CDMA in Band Class 0            and when            -   1≦CHANNEL_NUMBER≦313 or            -   991≦CHANNEL_NUMBER≦1023,        -    set the General Purpose Input Output X1 (GPIOX1) to inform            the LTE sub-system that a potential interference problem            exists. The channel numbers can correspond to frequencies            where a previous calculation has determined interference can            exist if the LTE system is transmitting the wrong resource            blocks. The state of GPIOX1 shall be held until the modem            stops transmitting for any of the reasons noted below.            -   i. The CDMA sub-system sends a Release Order to the                network.            -   ii. The CDMA sub-system receives a Release Order from                the network.            -   iii. The call is dropped through signal loss from the                network.        -   c. When GPIOX1 is set, the CDMA sub-system can send the            measured transmit power (P_CDMA) to the LTE sub-system once            every 5 milliseconds over the UART connecting the two            modems. For example, that the power control groups in CDMA            can operate on 1.25 millisecond boundaries, while those in            LTE can operate on 1 millisecond boundaries. The choice of 5            milliseconds can allow the two sub-systems to adjust their            power on fixed boundaries. This can induce a possible error            of 4 power control adjustments on the CDMA side and 5 on the            LTE side.            -   i. The data can be transmitted in signed integer format                (8 bit field) that ranges from +127 to −128 dBm, with                valid powers within the range +30 to −64 dBm.    -   2. Procedures for LTE Side        -   a. When the CHANNEL NUMBER and PMIN CDMA CDMA information            message is received from the CDMA sub-system, the LTE            sub-system can calculate the resource block limitations            (RB_NUM_LOW and RB_NUM_HIGH) based upon the formula below.            -   i. IF 1≦N≦799 (where N=the operational CDMA channel)                RB_NUM_LOW=INT[(3*CHANNEL_NUMBER−INT_BW+241)/18]                RB_NUM_HIGH=INT[(3*CHANNEL_NUMBER+INT_BW+241)/18]            -   ii. ELSEIF 991≦N≦1023                RB_NUM_LOW=INT[(3*CHANNEL_NUMBER−INT_BW−2828)/18]                RB_NUM_HIGH=INT[(3*CHANNEL_NUMBER+INT_BW−2828)/18]            -    where INT_BW=264, which corresponds to a 2.64 MHz                interference bandwidth.        -   b. When GPIOX1 is set, the LTE sub-system can receive the            measured CDMA transmit power, P_CDMA, from the CDMA            sub-system over the Universal Asynchronous            Receiver/Transmitter (UART) connection.            -   i. If any resource blocks fall within the range            -    RB_NUM_LOW≦RB≦RB_(≦)NUM_HIGH,            -    then the LTE sub-system can calculate the power cutback                for bearer resource blocks per the following formula:                LTE_PWR_RED_SVLTE_CDMA=2*(P_CDMA−P_MIN_CDMA_CDMA)−10*log                (NUM_OF_RB)            -    According to one example, this formula can be                determined based on the fact that the interference can                be third order and proportional to twice the CDMA                transmit power and proportional to 1× the LTE transmit                power. Furthermore, the power can be proportional to the                LTE operating bandwidth, which can be defined by the                number of active resource blocks. Note that if any                resource blocks fall within the interference range, then                the power reduction calculation can be based upon the                number of resource blocks (NUM_OF_RB) that fall within                the RB_NUM_LOW≦RB≦RB_NUM_HIGH limits.            -   ii. The LTE sub-system can reduce the maximum transmit                power of the resource blocks that fall within the                interference range (RB_NUM_LOW≦RB≦RB_NUM_HIGH) per the                following constraints.                -   1. Resource blocks that contain signaling may not                    have their maximum transmit power reduced.                -   2. Resource blocks that do not contain signaling may                    have their maximum transmit power reduced by                    LTE_PWR_RED_SVLTE_CDMA. Note that the power                    reduction limitation can be with respect to the                    maximum transmit power of the device and not                    necessarily the dynamic transmit power of the LTE                    sub-system. The overall effect of the reduction in                    many cases may result in no change in the LTE                    transmit power, as this can change the maximum power                    limit.

As an example for Conversion of Channel Number to Frequency for BandClass 0, if the terminal CDMA channel number is 1≦N≦799, the CDMA centerfrequency can be 0.030 N+825.000 MHz. If the terminal CDMA channelnumber is 991≦N≦1023, the CDMA center frequency can be 0.030(N−1023)+825.000 MHz. If the base station CDMA channel number is1≦N≦799, the CDMA center frequency can be 0.030 N+870.000 MHz. If thebase station CDMA channel number is 991≦N≦1023, the CDMA centerfrequency can be 0.030 (N−1023)+870.000 MHz.

As an example for Conversion of Resource Block Number to Frequency forBand 13, if the terminal LTE Resource Block (RB) number is 1≦RBt≦50,that LTE Resource Block center frequency can be 0.18 RBt+777.590 MHz. Ifthe base station LTE Resource Block (RB) number is 1≦RBr≦50, that LTEResource Block center frequency can be 0.18 RBr+746 MHz.

FIG. 2 is an example block diagram of a wireless communication device200, such as the terminal 110, according to a possible embodiment. Thewireless communication device 200 can include a housing 210, acontroller 220 located within the housing 210, audio input and outputcircuitry 230 coupled to the controller 220, a display 240 coupled tothe controller 220, a first transceiver 250 coupled to the controller220, a first antenna 255 coupled to the first transceiver 250, a secondtransceiver 252 coupled to the controller 220, a second antenna 257coupled to the second transceiver 252, a user interface 260 coupled tothe controller 220, and a memory 270 coupled to the controller 220. Thewireless communication device 200 can also include a power cutbackmodule 290. The power cutback module 290 can be coupled to thecontroller 220, can reside within the controller 220, can reside withinthe memory 270, can be an autonomous module, can be software, can behardware, or can be in any other format useful for a module for awireless communication device 200.

The display 240 can be a liquid crystal display (LCD), a light emittingdiode (LED) display, a plasma display, a touch screen display, aprojector, or any other means for displaying information. Other methodscan be used to present information to a user, such as aurally through aspeaker or kinesthetically through a vibrator. The transceivers 250and/or 252 may include transmitters and/or receivers. The audio inputand output circuitry 230 can include a microphone, a speaker, atransducer, or any other audio input and output circuitry. The userinterface 260 can include a keypad, buttons, a touch pad, a joystick, anadditional display, a touch screen display, or any other device usefulfor providing an interface between a user and an electronic device. Thememory 270 can include a random access memory, a read only memory, anoptical memory, a subscriber identity module memory, flash memory, orany other memory that can be coupled to a wireless communication device.

In operation, the first transceiver 250 can transmit in a firstfrequency band. The second transceiver 252 can transmit in a secondfrequency band. The controller 220 can control operations of thewireless communication device 200. The power cutback module 290 candetermine if a transmit frequency in the first frequency band combinedwith a transmit frequency in the second frequency band causes receiverdesensitization. The power cutback module 290 can determine if thetransmit power in the first frequency band is above a threshold power.The power cutback module 290 can reduce the maximum transmit power inthe second frequency band by an amount proportional to transmit power inthe first frequency band and transmit signal bandwidth in the secondfrequency band if the transmit frequency in the first frequency bandcombined with the transmit frequency in the second frequency band causesreceiver desensitization at the device 200 and if the transmit power inthe first frequency band is above the threshold power.

The power cutback module 290 may reduce the maximum transmit power inthe second frequency band in only the portion of the second frequencyband where a resultant frequency component can cause desensitization.The power cutback module 290 may also reduce the maximum transmit powerin the second frequency band in only the portion of the second frequencyband where a resultant frequency component can cause desensitization inthe sub-portion of that second frequency band that does not containsignaling. The power cutback module 290 can reduce the maximum power inthe second frequency band based on a formula including: two multipliedby (first frequency band transmit power minus a threshold) minus (anamount inversely proportional to the bandwidth of transmit bandwidth inthe second frequency band). For example, the power cutback module canreduce the maximum power in the second frequency band based on a formulaincluding: 2*(Tx₁−Th)−(1/BW₂), where Tx₁ comprises a first frequencyband transmit power, where Th comprises a threshold for the firstfrequency band transmit power, and where 1/BW₂ comprises an amountinversely proportional to the bandwidth of transmit bandwidth in thesecond frequency band. The power cutback module 290 can calculate aninterfering bandwidth between the first frequency band and the secondfrequency band and can reduce the maximum transmit power in the secondfrequency band based on the calculated interfering bandwidth. Forexample, the power adjustment can depend upon the calculated interferingbandwidth, the part of a LTE waveform that creates interference can becalculated, and then the power can be adjusted appropriately for thatbandwidth. The interference calculation can be performed on the activeportion of the LTE waveform and a determination can be made that no realinterference exists if the active portion, such as the portion includingallocated resource blocks, does not actually create interference. Thetransmit power in the second frequency band can be inverselyproportional to a number transmitted of resource blocks.

The controller 220 can operate the wireless communication device 200 ina simultaneous call in the first frequency band and in the secondfrequency band. The power cutback module 290 can determine receiversensitization while operating the device 200 in a simultaneous call inthe first frequency band and in the second frequency band. The firstfrequency band can be a CDMA radio frequency band and the secondfrequency band can be LTE radio frequency band. The power cutback module290 can determine if the transmit frequency in the first frequency bandfrom the device 200 combined with a simultaneous transmit frequency inthe second frequency band from the device 200 causes receiverdesensitization at the device 200.

FIG. 3 illustrates an example flowchart 300 illustrating the operationof the wireless communication device 200 according to one possibleembodiment. For example, the flowchart 300 can illustrate a method ofoperating a dual frequency band transmit device. As a further example,the method can be performed in a LTE modem at a baseband level beforetransmission. The method can reduce transmit power in a frequency bandby an amount proportional to transmit signal bandwidth. At 310, theflowchart can begin.

At 320, a determination can be made whether a transmit frequency in afirst frequency band from the device combined with a transmit frequencyin a second frequency band from the device causes receiverdesensitization at the device. According to one embodiment, the firstfrequency band can be a CDMA radio frequency band and the secondfrequency band can be a LTE radio frequency band. The frequency bandscan be other cellular wireless technology frequency bands. For example,the second frequency band can be a UMTS frequency band. Receiverdesensitization can be a reduction in receiver sensitivity due to thepresence of a high-level off-channel signal overloading theradio-frequency amplifier or mixer stages.

For example, receiver desensitization can occur when a strongoff-channel signal overloads a receiver front end and thus reduces thesensitivity to weaker on-channel signals. For example, receiverdesensitization can occur when two off-channel signals combine in anon-linear device to create an on-channel signal that reduces thereceiver front end's sensitivity to on-channel signals. Determiningreceiver desensitization can include determining if transmitting at thetransmit frequency in the first frequency band from the device combinedwith simultaneous transmitting at the transmit frequency in the secondfrequency band from the device causes receiver desensitization at thedevice.

If the combination of transmit frequencies causes receiverdesensitization, at 330, a determination can be made whether transmitpower in the first frequency band is above a threshold power. At 340, iftransmit power in the first frequency band is above the threshold power,a maximum transmit power can be reduced in the second frequency band byan amount proportional to transmit power in the first frequency band andtransmit signal bandwidth in the second frequency band. Reducing caninclude reducing the maximum transmit power in the second frequency bandin only the portion of the second frequency band where a resultantfrequency component can cause desensitization. Reducing can includereducing the maximum transmit power in the second frequency band in onlythe portion of the second frequency band where a resultant frequencycomponent can cause desensitization and signaling is not beingtransmitted. Reducing can include reducing the maximum power in thesecond frequency band based on a formula including: 2*(first frequencyband transmit power−threshold)−(an amount inversely proportional to thebandwidth of transmit bandwidth in the second frequency band). Thetransmit power in the second frequency band can be inverselyproportional to a number of transmitted resource blocks. At 350, thedevice can transmit a call in the second frequency band simultaneouswith reduced maximum transmit power and in the first frequency band.

At 350, the flowchart 300 can end. According to some embodiments, all ofthe blocks of the flowchart 300 may not be necessary. Additionally, theflowchart 300 or blocks of the flowchart 300 may be performed numeroustimes, such as iteratively. For example, the flowchart 300 may loop backfrom later blocks to earlier blocks. Furthermore, many of the blocks canbe performed concurrently or in parallel processes.

FIG. 4 illustrates an example flowchart 400 illustrating the operationof the wireless communication device 200 according to one possibleembodiment. At 410, the flowchart 400 begins. At 420, an interferingbandwidth between a first frequency band and a second frequency band canbe calculated.

At 430, the maximum transmit power in the second frequency band can bereduced based on the calculated interfering bandwidth. For example, thepower adjustment can depend upon the calculated interfering bandwidth.The part of the LTE waveform that creates interference can becalculated, and then the power can be adjusted appropriately for thatbandwidth. The interference calculation can be performed on the activeportion of the LTE waveform and a determination can be made that no realinterference exists if the active portion, such as the portion includingallocated resource blocks, does not actually create interference.

At 440, the device can operate in a simultaneous call in the firstfrequency band and in the second frequency band. For example, the firstfrequency band can be transmitted using a first frequency bandtransmitter and the second frequency band can be transmitted using asecond frequency band transmitter. Determining receiver sensitizationcan be performed before operating the device in a simultaneous call inthe first frequency band and in the second frequency band and/or can beperformed while or after operating the device in a simultaneous call inthe first frequency band and in the second frequency band.

Elements of the flowchart 400 can be combined with elements of theflowchart 300. For example, elements of the flowchart 400 can be addedto the flowchart 300 as described in earlier embodiments. According tosome embodiments, all of the blocks of the flowchart 400 may not benecessary. Additionally, the flowchart 400 or blocks of the flowchart400 may be performed numerous times, such as iteratively. For example,the flowchart 400 may loop back from later blocks to earlier blocks.Furthermore, many of the blocks can be performed concurrently or inparallel processes.

The methods of this disclosure may be implemented on a programmedprocessor. However, the operations of the embodiments may also beimplemented on non-transitory machine readable storage having storedthereon a computer program having a plurality of code sections thatinclude the blocks illustrated in the flowcharts, or a general purposeor special purpose computer, a programmed microprocessor ormicrocontroller and peripheral integrated circuit elements, anintegrated circuit, a hardware electronic or logic circuit such as adiscrete element circuit, a programmable logic device, or the like. Ingeneral, any device on which resides a finite state machine capable ofimplementing the operations of the embodiments may be used to implementthe processor functions of this disclosure.

While this disclosure has been described with specific embodimentsthereof, it is evident that many alternatives, modifications, andvariations will be apparent to those skilled in the art. For example,various components of the embodiments may be interchanged, added, orsubstituted in the other embodiments. Also, all of the elements of eachfigure are not necessary for operation of the disclosed embodiments. Forexample, one of ordinary skill in the art of the disclosed embodimentswould be enabled to make and use the teachings of the disclosure bysimply employing the elements of the independent claims. Accordingly,the embodiments of the disclosure as set forth herein are intended to beillustrative, not limiting. Various changes may be made withoutdeparting from the spirit and scope of the disclosure.

In this document, relational terms such as “first,” “second,” and thelike may be used solely to distinguish one entity or action from anotherentity or action without necessarily requiring or implying any actualsuch relationship or order between such entities or actions. The term“coupled,” unless otherwise modified, implies that elements may beconnected together, but does not require a direct connection. Forexample, elements may be connected through one or more interveningelements. Furthermore, two elements may be coupled by using physicalconnections between the elements, by using electrical signals betweenthe elements, by using radio frequency signals between the elements, byusing optical signals between the elements, by providing functionalinteraction between the elements, or by otherwise relating two elementstogether. Also, relational terms, such as “top,” “bottom,” “front,”“back,” “horizontal,” “vertical,” and the like may be used solely todistinguish a spatial orientation of elements relative to each other andwithout necessarily implying a spatial orientation relative to any otherphysical coordinate system. The terms “comprises,” “comprising,” or anyother variation thereof, are intended to cover a non-exclusiveinclusion, such that a process, method, article, or apparatus thatcomprises a list of elements does not include only those elements butmay include other elements not expressly listed or inherent to suchprocess, method, article, or apparatus. An element proceeded by “a,”“an,” or the like does not, without more constraints, preclude theexistence of additional identical elements in the process, method,article, or apparatus that comprises the element. Also, the term“another” is defined as at least a second or more. The terms“including,” “having,” and the like, as used herein, are defined as“comprising.”

We claim:
 1. A method of operating a dual frequency band transmitdevice, the method comprising: determining if a transmit frequency in afirst frequency band from the device combined with a transmit frequencyin a second frequency band from the device causes receiverdesensitization at the device; determining if transmit power in thefirst frequency band is above a threshold power; and reducing maximumtransmit power in the second frequency band by an amount inverselyproportional to transmit signal bandwidth in the second frequency bandif the transmit frequency in the first frequency band combined with thetransmit frequency in the second frequency band causes receiverdesensitization at the device and if the transmit power in the firstfrequency band is above the threshold power.
 2. The method according toclaim 1, wherein reducing comprises reducing the maximum transmit powerin the second frequency band in only the portion of the second frequencyband where a resultant frequency component can cause desensitization. 3.The method according to claim 1, wherein reducing comprises changing themaximum transmit power in the second frequency band in a sub-portion ofthe second frequency band where a resultant frequency component cancause desensitization if that sub-portion is not transmitting signalinginformation.
 4. The method according to claim 1, further comprisingoperating the transmit device in a simultaneous call in the firstfrequency band and in the second frequency band, wherein determiningreceiver sensitization is performed while operating the transmit devicein a simultaneous call in the first frequency band and in the secondfrequency band.
 5. The method according to claim 1, further comprising:transmitting the first frequency band using a first frequency bandtransmitter; and transmitting the second frequency band using a secondfrequency band transmitter.
 6. The method according to claim 1, whereinthe first frequency band comprises a code division multiple access radiofrequency band and wherein the second frequency band comprises a longterm evolution radio frequency band.
 7. The method according to claim 1,wherein determining receiver desensitization comprises determining iftransmitting at the transmit frequency in the first frequency band fromthe device combined with simultaneous transmitting at the transmitfrequency in the second frequency band from the device causes receiverdesensitization at the device.
 8. The method according to claim 1,wherein reducing maximum transmit power in the second frequency bandbeing reducing the maximum transmit power in the second frequency bandby an amount proportional to the transmit power in the first frequencyband and inversely proportional to the transmit signal bandwidth in thesecond frequency band if the transmit frequency in the first frequencyband combined with the transmit frequency in the second frequency bandcaused receiver desensitization at the device and if the transmit powerin the first frequency band is above the threshold power.
 9. Anapparatus comprising: a first transceiver configured to transmit in afirst frequency band; a second transceiver configured to transmit in asecond frequency band; a controller coupled to the first transceiver andthe second transceiver, the controller configured to control operationsof the apparatus; a power cutback module coupled to the controller, thepower cutback module configured to determine if a transmit frequency inthe first frequency band combined with a transmit frequency in thesecond frequency band causes receiver desensitization, configured todetermine if transmit power in the first frequency band is above athreshold power, and configured to reduce the maximum transmit power inthe second frequency band by an amount inversely proportional transmitsignal bandwidth in the second frequency band if the transmit frequencyin the first frequency band combined with the transmit frequency in thesecond frequency band causes receiver desensitization at the device andif the transmit power in the first frequency band is above the thresholdpower.
 10. The apparatus according to claim 9, wherein the power cutbackmodule is configured to reduce the maximum transmit power in the secondfrequency band in only the portion of the second frequency band where aresultant frequency component can cause desensitization.
 11. Theapparatus according to claim 9, wherein the power cutback module isconfigured to reduce the maximum transmit power in the second frequencyband in a sub-portion of the second frequency band where a resultantfrequency component can cause desensitization if that sub-portion is nottransmitting signaling information.
 12. The apparatus according to claim9, wherein the power cutback module is configured to determine if thetransmit frequency in the first frequency band from the device combinedwith a simultaneous transmit frequency in the second frequency band fromthe device causes receiver desensitization at the device.
 13. Theapparatus according to claim 9, wherein the power cutback module isconfigured to reduce the maximum transmit power in the second frequencyband by an amount proportional to the transmit power in the firstfrequency band and inversely proportional to the transmit signalbandwidth in the second frequency band if the transmit frequency in thefirst frequency band combined with the transmit frequency in the secondfrequency band caused receiver desensitization at the device and if thetransmit power in the first frequency band is above the threshold power.14. An apparatus comprising: a first transceiver configured to transmitin a first frequency band at a transmit power; a second transceiverconfigured to transmit in a second frequency band; a controller coupledto the first transceiver and the second transceiver, the controllerconfigured to control operations of the apparatus; a user interfacecoupled to the controller, the user input configured to receive inputfrom a user; a power cutback module coupled to the controller, the powercutback module configured to determine if a transmit frequency in thefirst frequency band combined with a transmit frequency in the secondfrequency band causes receiver desensitization, configured to determineif the transmit power in the first frequency band is above a thresholdpower, and configured to reduce maximum transmit power in the secondfrequency band by an amount inversely proportional to transmit signalbandwidth in the second frequency band if the transmit frequency in thefirst frequency band combined with the transmit frequency in the secondfrequency band causes receiver desensitization at the device and if thetransmit power in the first frequency band is above the threshold power,wherein desensitization comprises reduced receiver sensitivity from astrong off-channel signal overloading a receiver front end and reducingthe sensitivity to weaker on-channel signals.
 15. The apparatusaccording to claim 14, wherein the power cutback module is configured toreduce the maximum transmit power in the second frequency band in onlythe portion of the second frequency band where a resultant frequencycomponent causes desensitization.
 16. The apparatus according to claim14, wherein the power cutback module is configured to reduce the maximumtransmit power in the second frequency band by an amount proportional tothe transmit power in the first frequency band and inverselyproportional to the transmit signal bandwidth in the second frequencyband if the transmit frequency in the first frequency band combined withthe transmit frequency in the second frequency band caused receiverdesensitization at the device and if the transmit power in the firstfrequency band is above the threshold power.